Fluid-operated percussive tool.



L. G, BAYLES. FLUID OPERATED PERGUSSIVE TOOL.

APPLIGATION FILED 111111.14, 1914.

Patented May 19, 1914.

2 $HEETS-SHEET l.

INI/ENTOR M Q sn g,

Arm/Mr of Pennsylvania, have UNITED-STATES LEWIS c. BAYLES, 0r sas'rou,PENNSYLVANIA,

FLUID-OPERATED Specification otietters Patent.

ASSIGNOB TO INGIE IRSOLL-BAND COMPANY, OF JERSEY CITY,- NEW JERSEY, ACORPORATION OF NEW JERSEY.

FERGUSSIVE TOOL.

Be it known that I, LEWIS C. Burns, a citizen of the United States,residing at Easton, in thecounty of Northampton and State invented acertain new. and useful Improvement inl lluidrOp: erated'Percussive'llo'ols Case 13,) of which a the following is a specification.

This invention relates to fluid operated percussive tools and moreparticularly to the type 'of tool wherein one surface of the piston isexposed to constant fluid pressure for driving it in one direction whileanother opposed larger surface is exposed to intermittent fluid pressurefor driving it in the other direction, the admission of the fluidpressure to the larger surface being controlled by the movement of thepiston.

The object of this invention is to provide a means whereby, although theadmission to the larger surface of the piston takes place near the'endof the piston stroke under con stant pressure, this admission iscontinued through a larger portion of the return pis-.

28- ton stroke, the closing of the passage conveying fluid t0 the largersurface being delayed during the return stroke. With this object inView, a mechanism has been devised practical embodiments of which areshown .in' the accompanying drawings in which:

Figure 1 shows an elevation of the exterior of the tool, Fig, '2, alongitudinal section taken on the line II-1I of Fig. 1, Figs. 3 to (S,diagrammatic views showin g the piston and controlling valve in variouspositions,

and Fig. 7, a detail showing a modified form of controlling valve.

""lhe tool is shown in the drawings as a drill comprising a cylinder 1in which is a bore of two diameters forming a larger forward cylinderEhamber 2 and a snialler rearwafdfi'linder chamber 3. In the cylinder 1rcciprocates a piston comprising a head 1 fitting the larger cylinderchamber and a shank5 fittin the smaller cylinder chamber,

the bore of the cylinder head 8 Air is 'ad-" between which is areduced'portion or neck 6. Theliead 4 of the piston strikes on an 7' Vanvillblbck 7 which in turn actuates a drill .steel', not shown, whichis loosely inserted in mitted to-the rear end of the smaller cylinderchamber 3 through an inlet passage 9 so that-a. constant fluid pressureis always cxcrted, during the operation of the tool on The rear face ofthe cylinder head 4 is also exposed to fluid pressureduring a portion ofthe forward stroke of the piston through passages 10 which lead from therear end of the small cylinder chamber 3 through ports vinuthesidejithisnhambend so placed as to be connected with the rear end of thelarger piston is at'or near the end of its stroke.

Extending from one end of the piston to passage to convey fluid from theconstantly supplied rear end of the cylinder to the forward end.Reciprocally mounted in the back head 12 of the drill is a valve 13which is in the form of a rod projecting for a 0011- siderable distanceinto the cy inder and sliding into the bore 11 of the piston. -Therearward portion of this valve 13 fits closely into the bore 11 andprevents any fluid from passing therethrough into the forward end valve13 however are a series of depressions or grooves 14 which are uncoveredby the rear end of the piston shank. 5 near the forward end of itsforward stroke andadmit bore 11 and hence to the forward end of thccylinder. The rear end of the valve 13 is provided with a head 15 whichslides in a chamber 16 and limits the reciprocating movement of thevalve 13. To this chamber 16 a small leak passage 17 leads from the rearend of the cylinder whereas'a larger passage 18 leads to the atmospherethrough in the chamber 16. Exhaust from the forwardend of the cylinderand also from'the chamber which is also.inter1n1ttent y supplied isafforded through the exhaust port larger cylinder chamber and exhaustsby a passage 21 to atmosphere through the port '19.

The operation of the tool can be easily seen from Figs. 8 to 6. pin 3the parts are shown as the piston is just nearing the end of its forwardstroke and the rear end of the shank has just uncovered the grooves 14in tlievalve 13. Fluid will then be admitted to the forward end of thecylinder checkin the forward movement of the pis- Patented May 19, 191a.Application filed January 14, 1914. Serial No. 811,987.

bore 2 by the neck (3 of the piston when the i the other is a bore 11which serves as a.

of the cylinder; in the forward end of the fluid from the rear end ofthe cylinder to the rearward portion of the larger, 0 linder' 20, whichis placed at about the center of the the exhaust port 19, a constantreduced pressure being therefore continually maintained I admission offluid to tilgie passage 11 also exposes the forward e'ndihf the valve 13to the full admission pressure of the fluid. As the pressure .in thechamber 16 on the headof the valve 13 is less than this admission pressure, by reason of. the fact that passage 18 is larger than the passage17, the valve 13 will be moved rearwardly at some time duringthe periodwhen the iston is in the for ward part ofthe cylin or, it being;immaterial exactly when. This position of the parts is shown in Fig. 4,In these positions it can be seen also that any pressure in the rear endof the larger chamber 2'is free to exhaust through the exhaust port 20.By son of the rearward movement of the ve 13 it will be seen. that thepassage 11 'ven a greater ellicient length for admis sion through therearward stroke of the pieton and that therefore although the admis sionof-fiuid to the forward end of the cylinder does not commence until thepiston has nearly reached. the torwarden'd of its stroke. The shuttingoff of the admission to the forward end of the Icylinder is delayed onits return stroke until the piston has traveled an additional distanceequal to the movement of the valve 15. When the piston on its returnstroke reaches the position. shown in Fig. 5 admission to the front endof the cylinder throughthe passage 11 has been closed and the exhaustport 20 opened by the front face of the piston so that the forward endof the cylinder is exhausted. This relieves the pressure on the frontend of the valve 13 and the cons-ant reduced pressure in the chamber 16against the head 15 of the valve returns it to the position shown in Pg:6. The piston is then free to move forward again, its forward movementbeing accomplished not only on the shank 5 but also by the pressure offluid on the rear face oi? the a on head 4 which is admitted as shownin. l. igs. 5 and G to the rear end of the larger cyliuder chamher 2 byway of passages 10 and th neclt (i of the piston.

In Fig. 7 is shown a modified :torn of the valve \vh'icl': is providedwith a lJClUCQQl stem 21 which passes through the hue c head of thecylinder, the chamber. 16 being open to atmosphere so that. there is nopressure on the head 15. The rear SlllfllCCyOil the shoulder 22 is lessthan the forwardleud hf the valve so that when pressure xerted on theforward end of the valve tlnl valve will move rearwardly while when thhprelisure is exhausted'from the forward and a." the valve the valveivillmore forwardly by reusmiof the pressure on the shoulder- 22, in bothforms there being a less 1 res-",- sure area tending to move the valvefo than that to move it rearward.

It is; to be understood that the resort showing and descriptiondiscloses 0 1y carrby the constant pressurev tain specifiedmodifications of my invention and other forms'and modifications areineluded in the spirit and scope of the invention as expressed in theclaims.

What I claim is:

1. In a percussive tool, acylinder, a pie ton, I'HQLLHS for constantlyadmitting fluid to one end of the cylinder, a passage lead nig from saidconstant pressure end 0t said cylinder to the opposite end of thecylinder and arranged to he opened by the movement oi: the p1ston nearthe end or 1ts stroke,

and a valve controlling said passage, said 4 valve moving to delay theclosing of said passage by said piston on its return stroke.

2. In a percussive tool, a cylinder, a piston having differentialpressure areas, means for admitting constant fluid pressure to one end.of the cylinder, to becxerted on the smaller piston area, a passage forconveying fluid from the constant pressure end of the cylinder to theopposite end of the cylinder, said passage being opened by the pistonnear-the end of its stroke, and a valve forincrcasing the effectivelength of said passage onthe return stroke of said piston, to delay theclosing of said passage.

3. In a percussive drill, a cylinder, a piston, means for constantlyadmitting pressure to one end of the cylinder, a passage for admittingfluid to the other end, a valve for controlling the period of admissionthrough said passage, said valve having an operating surface exposed tothe pressure oi? the fluid in said passage, and an opening controlled bythe movement of thepiston foriulmitting fluid to said passage near theend oi its stroke. under constant pressure, the pressure of said fluidserving to move said valvc to lengthen the admission period through saidpassage during the return of said piston.

1'. In a percussive tool, a cylinder, a piston, means for constantlyadmitting pressure to one end i the cylinder, a passage forintermittently admitting fluid to the other end, a valve for controllingthe period oi admission through said passage, said valve having anoperating surface exposed to the pressure 01' the iluid in said passageand a less el'l'ectivc opposed operating sur- .ace exposed to constantpressure, an opening controlled by the movement of ion foradmittinglluid to said the end oil? its stroke under constant pressure,the pressure 01 said fluid serving to move said valve to lengthen theadmission period through said passage during the return of said piston,and exhaust means for the intermittently supplied cylinder end.

5. In a. percussive tool, cylinder of two diameters, piston of two diameters therein, having two small pressure areas for driving it in onedirection and one larger area for driving it in the other direction,means passage near the pismovement of the piston, and a for constantiyadmitting fl iei pressure to the cylinder against one said smallersurfaces, means for ioternf jt-entiy admitting pressure to the other ofsaid smaller surfaces, a passage ffrom said constant precsure portion ofthe oyiimier fiuici against. the larger piston 51L passage being openedclose] to delay the closing thereof by said piston during its returnstroke.

6. In a ercussive t-ooL a o ilnoier, a

, e] 1 toiibmeans for constantl sm pressure to one end or the 0y a @337sage through the plsion to the; other I creasing the efieotive length othe cylinder, and s valve projecting into' said valve resrwardiy todelayton, a joasssge for constantly admiili-ing fluid pressure to one end ofthe cylinder, a bore 4 sure surface on said vel zve exposed to thepressure bore, and servin to move too closmg of said bore on shereturnstro e of the piston, a less efieciive constant pressure area,

on said. valve to move it forwardly, am means to exhaust theintermittently supplied end of he cylinder, near the end of rho returnpiston siroke. v In testimori whereof, I'have hereunto set my hand.

LEW is C. BAXLES.

Witnesses Vi M, grams, RUSSELL H. Wnirrs m.

